Polarization inspection device

Abstract

A polarization inspector for inspecting an inspection target, the polarization inspector having a polarization divider for spatially dividing at least a reflected beam of light from the inspection target by irradiating an illumination beam into divided beams of lights mutually different in polarization direction; one or more optical receivers for receiving the divided beams of lights and generating an image signal based on the divided beams of lights; and a processor for calculating at least one of an elliptical azimuth angle, a polarization degree and a polarization component intensity from the image signal.

What is claimed is: 
     
       1. A polarization inspector for inspecting an inspection target, the polarization inspector comprising:
 a polarization divider configured to spatially divide at least a reflected beam of light from the inspection target into divided beams of lights which are mutually different in polarization direction; 
 one or more optical receivers configured to receive the divided beams of lights and to generate an image signal based on the divided beams of lights; and 
 a processor configured to calculate at least one of an elliptical azimuth angle, a polarization degree and a polarization component intensity from the image signal, 
 
       wherein
 the polarization divider comprises: 
 a beam splitter configured to split at least the reflected beam of light having the polarization direction obtained from the inspection target into a first split beam of light and a second split beam of light; 
 a wavelength device configured to rotate by 45 degrees either one of the first split beam of light or the second split beam of light to differentiate in polarization direction by 45 degrees between the first split beam of light and the second split beam of light; and 
 a polarization dividing element configured to obtain the first split beam which was not transmitted through the wavelength device and the second split beam which was transmitted through the wavelength device, to divide each of the first split beam and the second split beam into plural divided lights of which the polarization directions are mutually perpendicular, and wherein 
 the polarization dividing element comprises: 
 a first optical member that comprises a first trapezoidal prism, a first diamond-shaped prism, and a first triangular prism are mutually bonded; and 
 a second optical member that comprises a second trapezoidal prism, a second diamond-shaped prism, and a second triangular prism are mutually bonded; wherein 
 the first optical member and the second optical member are bonded such that the surface of the first diamond-shaped prism of the first optical member and the surface of the second diamond-shaped prism of the second optical member are perpendicular. 
 
     
     
       2. The polarization inspector according to  claim 1 , wherein
 the surface of which the first trapezoidal prism and the first diamond-shaped prism are bonded is a translucent surface, and 
 each the surface of which the first diamond-shaped prism and the first triangular prism of the first optical member are bonded, the surface of which the second trapezoidal prism and the second diamond-shaped prism of the second optical member are bonded, and the surface of which the second diamond-shaped prism and the second triangular prism of the second optical member are bonded is a total reflection surface. 
 
     
     
       3. The polarization inspector according to  claim 2 , wherein
 the optical receiver comprises an image sensor configured to independently obtain each of the plural divided beams of lights which are divided by the polarization divider in mutually different areas of an imaging surface. 
 
     
     
       4. The polarization inspector according to  claim 1 , wherein
 the optical receiver comprises an image sensor configured to independently obtain each of the plural divided beams of lights which are divided by the polarization divider in mutually different areas of an imaging surface. 
 
     
     
       5. The polarization inspector according to  claim 1 , wherein
 the optical receiver comprises an image sensor configured to independently obtain each of the plural divided beams of lights which are divided by the polarization divider in mutually different areas of an imaging surface. 
 
     
     
       6. The polarization inspector according to  claim 1 , wherein
 the optical receiver comprises an image sensor configured to independently obtain each of the plural divided beams of lights which are divided by the polarization divider in mutually different areas of an imaging surface. 
 
     
     
       7. The polarization inspector according to  claim 1 , wherein
 the polarization divider comprises: 
 a beam splitter configured to split at least the reflected beam of light obtained from the inspection target into a first split beam of light and a second split beam of light which proceeds to the mutually different directions; 
 a first divider configured to divide the first split beam of light into plural divided beams of lights of which the polarization directions are mutually perpendicular; and 
 a second divider configured to divide the second split beam of light into plural divided beams of lights of which the polarization directions are mutually perpendicular and each of the polarization directions form 45 degrees to the polarization directions of the divided beams of lights divided by the first divider. 
 
     
     
       8. The polarization inspector according to  claim 7 , wherein
 the first divider comprises a polarization dividing element configured to divide the first split beam of light into the plural divided beams of lights of which the polarization directions are mutually perpendicular; 
 the second divider comprises a wavelength device configured to rotate by 45 degrees the polarization direction of the second split beam of light and a polarization dividing element configured to divide the second split beam of light which transmitted through the wavelength device into the plural divided beams of lights of which the polarization directions are mutually perpendicular. 
 
     
     
       9. The polarization inspector according to  claim 8 , wherein
 the optical receiver comprises: 
 a first optical receiving element configured to independently obtain the plural respective divided beams of lights divided by the first divider in the mutually different areas of the imaging surface; and 
 a second optical receiving element configured to independently obtain the plural respective divided beams of lights divided by the second divider in the mutually different areas of the imaging surface. 
 
     
     
       10. The polarization inspector according to  claim 7 , wherein
 the first divider comprises a first polarization dividing element configured to divide the first split beam of light into the plural divided beams of lights of which the polarization directions are mutually perpendicular; 
 the second divider comprises a second polarization dividing element configured to divide the second split beam of light into the plural divided beams of lights of which the polarization directions are mutually perpendicular; 
 the first polarization dividing element is configured to arrange that the first polarization dividing element forms 45 degrees to the crystal axis direction of the first split beam of light; and 
 the second polarization dividing element is configured to arrange that the second polarization dividing element forms 45 degrees to the crystal axis direction of the second split beam of light. 
 
     
     
       11. The polarization inspector according to  claim 10 , wherein
 the optical receiver comprises: 
 a first optical receiving element configured to independently obtain the plural respective divided beams of lights divided by the first divider in the mutually different areas of the imaging surface; and 
 a second optical receiving element configured to independently obtain the plural respective divided beams of lights divided by the second divider in the mutually different areas of the imaging surface. 
 
     
     
       12. The polarization inspector according to  claim 7 , wherein
 the optical receiver comprises: 
 a first optical receiving element configured to independently obtain the plural respective divided beams of lights divided by the first divider in the mutually different areas of the imaging surface; and 
 a second optical receiving element configured to independently obtain the plural respective divided beams of lights divided by the second divider in the mutually different areas of the imaging surface. 
 
     
     
       13. The polarization inspector according to  claim 1 , wherein
 the optical receiver comprises optical receiving elements that are arranged in accordance with the plural respective divided beams of lights divided by the polarization divider. 
 
     
     
       14. The polarization inspector according to  claim 1 , wherein
 the optical receiver comprises optical receiving elements that are arranged in accordance with the plural respective divided beams of lights divided by the polarization divider. 
 
     
     
       15. The polarization inspector according to  claim 1 , wherein
 the optical receiver comprises optical receiving elements that are arranged in accordance with the plural respective divided beams of lights divided by the polarization divider. 
 
     
     
       16. The polarization inspector according to  claim 1 , further comprising:
 an irradiator configured to irradiate an illumination beam of light to the inspection target; wherein 
 the irradiator comprises a wavelength filter configured to pass only a light having a predefined wavelength or a light of a predefined wavelength band. 
 
     
     
       17. The polarization inspector according to  claims 1 , wherein
 the polarization divider is configured to spatially divide the reflected beam of light of which the illumination beam of light is reflected by the inspection target or the transmitted beam of light of which the illumination beam of light is transmitted through the inspection target into the plural divided beams of lights of which the polarization directions are mutually different. 
 
     
     
       18. A polarization divider configured to spatially divide at least a reflected beam of light from the inspection target into divided beams of lights which are mutually different in polarization direction, the polarization divider comprising:
 a beam splitter configured to split at least the reflected beam of light having the polarization direction obtained from the inspection target into a first split beam of light and a second split beam of light; 
 a wavelength device configured to rotate by 45 degrees either one of the first split beam of light or the second split beam of light to differentiate in polarization direction by 45 degrees between the first split beam of light and the second split beam of light; and 
 a polarization dividing element configured to obtain the first split beam which was not transmitted through the wavelength device and the second split beam which was transmitted through the wavelength device, to divide each of the first split beam and the second split beam into plural divided lights of which the polarization directions are mutually perpendicular, 
 wherein 
 the polarization dividing element comprises: 
 a first optical member that comprises a first trapezoidal prism, a first diamond-shaped prism, and a first triangular prism are mutually bonded; and 
 a second optical member that comprises a second trapezoidal prism, a second diamond-shaped prism, and a second triangular prism are mutually bonded; wherein 
 the first optical member and the second optical member are bonded that the surface of the first diamond-shaped prism of the first optical member and the surface of the second diamond-shaped prism of the second optical member are perpendicular.